OCs increase risk of VTE in women with factor V Leiden mutation

A recently published systematic literature review suggests that women who have a factor V Leiden mutation-and possibly those who have other thrombogenic mutations-who take combined oral contraceptives (COCs) are at greater risk for venous thromboembolism (VTE) (risk ratios of 1.3–25.1) and cerebral vein or cerebral sinus thrombosis than nonusers with mutations.

Whether the increased risk accompanies other hormonal contraceptive methods and whether the type of COC or duration of use modifies the risk is unclear. But to be safe, the authors of the review recommend that women with known thrombogenic mutations who wish to use hormonal contraceptives use progestin-only pills or levonorgestrel-releasing intrauterine devices.

Despite the increased risk, routine screening for thrombogenic mutations of women who wish to use COCs is not recommended because more than 92,000 carriers would have to be screened to prevent one VTE/COC death-a $300 million endeavor.